The media tycoon and former prime minister called his Uruguayan coach on Wednesday night after the Italian champions succumbed to the Swedish part-timers in their fifth defeat of the season.
''You have my full confidence." Berlusconi told Tabarez, according to newspaper reports.
A source close to the billionaire politician was unable to confirm the conversation but said Berlusconi had watched the game from the Rome headquarters of his Forza Italia party, and put the defeat down to "typical bad luck''.
The source said Berlusconi had telephoned the managing director, Adriano Galliani, in Gothenburg and asked him to "tell the boys that I'm happy with them and the way they fought''.
Tabarez was brought in on a one-year contract when the previous coach, Fabio Capello, left for Real Madrid following five seasons of success that included four Serie A titles and a European Cup. The defending champions are sixth in the league after a 3-0 defeat to Roma last Saturday.
That disappointment fuelled speculation that Milan may sack Tabarez and try to lure back Capello's predecessor, Arrigo Sacchi, whose job as Italy's national coach is now on the line.
Galliani dismissed such talk as nonsense in Gothenburg on Wednesday before the Champions' League match.
"Releasing a coach from his contract is not part of our rules of behaviour," Galliani said. "Therefore it's a big mistake to talk about releasing Tabarez. I've read reports that we've been in touch with Sacchi. We've got nothing of the sort in mind and the future will prove it," he said.
Milan took a 52nd-minute lead in Gothenburg through the Liberian striker George Weah but suddenly found themselves facing the possiblity of being knocked out after the Swedes scored twice in 10 minutes.
With Milan unsettled by the loss of Tomas Locatelli due to injury, substitute Erik Wahlstedt headed in Gothenburg's first in the 74th minute, with the second in the 84th coming from Niclas Alexandersson.
The defeat left Milan second in Group D with three points after just one win from three matches and with a huge incentive for revenge when they face Gothenburg at home on 30 October. Unbeaten Porto head the group with nine points.
Tabarez, whose team had claimed Gothenburg's winning goal was offside, said Milan had not deserved to lose.Reuse content